This document summarizes information about Giardia lamblia, including its discovery in 1681, morphology, life cycle, pathogenesis, clinical features, laboratory diagnosis, and treatment. Key points include: - G. lamblia, commonly known as giardia, is a cosmopolitan intestinal parasite that infects the duodenum and jejunum. - It has two forms - a pear-shaped trophozoite and an oval cyst. The infective form is the cyst which is passed in feces. - Its life cycle involves attachment in the small intestine, encystation and passage in feces, then excystation and multiplication in the new host. - Clinical features include

1. GIARDIA LAMBLIA
Dr Adil Raza
Assistant Professor
JNMC, AMU, Aligarh

2. • Discovered by Leeuwenhoek in 1681.
• Named by Prof. GIARD of Paris and Prof Lambl
of Prague.
DISTRIBUTION
• Cosmopolitan, more prevalent in children.
HABITAT
• Duodenum and upper jejunum

3. MORPHOLOGY
Trophozoite:
• Pear shaped with anterior
end rounded and
posterior end pointed.
• Measures 15×9×4 µM.
• Dorsal surface is convex
while ventral surface
there is sucking disk.
• It is bilaterally
symmetrical.
• It has one pair of nuclei
on each side of mid line.

4. • One pair of axostyle,
• one pair of parabasal
bodies present on the
axostyle.
• Four pairs of flagella
and four pairs of
blepheroplasts from
which flagella arise.
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5. Cyst
• Mature cyst is oval in
shape and measured
11-14 µM ×7-10 µM in
size.
• It has two pair of nuclei.
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6. LIFE CYCLE & PATHOGENECITY
• Incubation period varies from 9 to 15 days.
• Single host is required.
• Infective form is cysts.
• Infective dose is 100 cysts.
• Route of infection are:
– Feco-oral route
– Contaminated food and water.
– Sexual practices among homosexual males.

7. Giardia Life Cycle
2 trophozoites
released per cyst
Sucking disc used
for attachment
Multiply by binary
fission every 12 h
Cyst forms in
transit to colon

8. • By means of sucker it attaches to duodenum.
• Encystation occur commonly when trophozoite
transit down to large bowel. Within 30 min of
ingestion excystation occurs in the duodenum.
• The cyst hatches out two trophozoites.
• Which then multiply and cover all the duodenum
• villous atrophy,
• crypt hyperplasia,
• epithelial cell damage, and

9. • Extensive infiltration of the lamina propria by
plasma cells, lymphocytes, and
polymorphonuclear leukocytes.
• blunting of the microvillous border of
epithelial cells.
• Reduced digestion and absorption of solutes
may then cause osmotic diarrhea with gas
formation.

10. CLINICAL FEATURES
• The acute stage usually begins with a feeling of
intestinal uneasiness, followed by nausea and
anorexia.
• Low-grade fever and chill may also be early
symptoms.
• Subsequent symptoms may include explosive,
watery, foul-smelling diarrhea;
• Marked abdominal gurgling and distention
associated with the passage of foul gas; and perhaps
belching, with a foul taste.
• Upper or mid-epigastric cramps may also occur.

11. • Chronic infection in children may present: as
• failure to thrive
• Urticaria
• cholecystitis
• and pancreatitis
• Uncommon associated symptoms including
• arthritis
• retinal arteritis and iridocyclitis.

12. LABORATORY DIAGNOSIS
• Stool examination:
– Trophozoites may be found in loose stools, and
cysts may be found in formed stools.
– A series of three stools, one collected each day on
alternate days or within no more than 10 days, is
recommended.
• Immunological tests:
• ELISA from feaces
• Culture:
• Diamond’s media

13. • The Entero-Test :is a gelatin capsule containing a length
of nylon string to which a small weight is attached. On
ingestion, the capsule dissolves, the nylon string is
released, and peristaltic action pulls the weighted string
down into the duodenal area. While the string is in
place, the patient can drink some water.
• The end of the string is usually taped to the patient's
cheek during the recommended 4-h test time.
• When the string is retrieved,
• The mucus and fluid from the bile-stained portion of the
string are removed by pulling the string through pinched
fingers of a gloved hand

14. • Several drops of mucus are usually obtained.
Most workers examine the material as a direct
wet smear preparation (using low light intensity
and the x40 objective).
• TREATMENT:
– Metronidazole
– Tinidazole
– furazolidone